1. Field of the Invention
The present invention relates to a method of charging and discharging a non-aqueous electrolyte secondary battery.
2. Description of Related Art
In recent years, a non-aqueous electrolyte secondary battery has drawn attention as a high energy density battery. In the non-aqueous electrolyte secondary battery, the negative electrode active material is composed of metallic lithium, a carbon material, or an alloy capable of intercalating and deintercalating lithium ions, and the positive electrode active material is composed of a lithium-transition metal composite oxide represented by the chemical formula LiMO2 (where M is a transition metal).
A representative example of the lithium-transition metal composite oxide is lithium cobalt oxide (LiCoO2), which has already been in commercial use as a positive electrode active material for non-aqueous electrolyte secondary batteries.
Materials containing Mn or Ni have also been researched. As an example of the materials containing Mn, manganese oxide having a spinel structure has been researched as an active material.
A problem with the non-aqueous electrolyte secondary battery that uses the manganese oxide having a spinel structure as an active material has been that the structure of the manganese oxide degrades due to the phase change associated with battery charging, causing the battery performance to deteriorate.
Japanese Patent No. 3024636 discloses that high-temperature storage performance of a battery can be prevented from degrading by adding a Li—Ni—Co composite oxide to such a manganese oxide having a spinel structure. However, the present inventors have conducted a study and as a result have found that the method disclosed in the patent publication cannot achieve sufficient cycle performance.